John isaac thornycroft



1. THORNYCROFT.

DRAWING BOARD.

APPLICATION FILED MAR. 4. 1919,

Patented Sept. 23, 1919.

ll/Ill rinirn JOHN ISAAC THOR-NYCROFT, OF ISLE OF WIGHT, ENGLAND.

DRAWING-BOARD.

Specification of Letters Patent.

Patented Sept. 1919.

Application filed March 4, 1919. Serial No. 280,537.

To all whom it may concern:

Be it known that I, Sir JOHN ISAAC THORNYCROFT, F. R. S, a subject of the King of Great Britain and Ireland, residing at Isle of Wight, England, have invented Improvements in or Relating to Drawing-Boards, of which the following is a specification.

It is often desirable to be able to remove a drawing from a drawing board to which it is attached and again replace it in exactly the same position on the board.

For instance, when a new design for an engine, ship, or other apparatus, object or structure has to be worked out by a draftsman, it is usual to have several sheets of drawings in hand that are worked upon alternately. The common practice in such cases is to employ separate drawing boards for the several. sheets of drawings. It, however the several sheets of drawings would each be secured in turn to a single drawing board, for work to be done upon it, and a fter removal, be capable of being replaced upon the board and secured in exactly the same position in which it was previously secured, the use of several drawing iboards would be unnecessary. This however cannot be easily and quickly effected with any certainty when ordinary drawing pins are used to secure the sheets of drawings in place on a board.

Now the present invention has for its object to overcome this dilliculty.

For this purpose, a drawing board is provided at a suitable part thereof, conveniently near its top edge portion, with permanently attached pins or studs that project upward to a small height above-the surface of the board and are arranged at a suitable distance apart, and the sheets of drawing paper to be drawn upon are provided near their upper edges with similar accurately" spaced and shaped holes so that the perforated portions of each sheet in turn can be slipped over the fixed studs and then be firmly secured in place by clip devices adapted to fit over the corresponding edge of the drawing board and the studs and clamp the sheet of paper securely in place until it is desired to remove it when the clip devices can be easily and quickly removed to admit of another sheet oil, drawing paper, provided with similarly spaced and shaped holes, taking its place. By these means, each sheet of paper can be easily and quickly socured in position, and after removal, can be easily and accurately replaced in its former position, as and when required, the one drawing board serving for use with any desired number oi sheets of paper. Also, if desired, one or more sheets of more or less transparent material, for instance tracing paper or cloth, may loe accurately placed one upon the other, or upon a sheet of drawing paper, and secured in place for comparison of different views or figures on the super-posed sheets. Thus, when for example, it is desired to compare curves indicating different results or PCITOPIIHIHCCS under ditferent conditions, they can, when drawn on thinv transparent or translucent n'iaterial, for instance tracing paper, to the same scale, be easily and accurately superposed by placing the perforated sheets one upon the other and over the fixed studs and securing them in place on the drawing board by means of the clip devices, so that assuming the several figures to be drawn to the same scale, and that the base line and point oi origin of each of them bear the same relation to the perforations in the sheets, they can be easily and accurately compared.

The studs are preferably of short cylindrical shape, and accurately spaced at a predetermined distance apart on the board and the holes inthe sheets of paper are accurately out and spaced to correspond. Sheets of drawing paper thus perforated can be easily suspended in any suitable box when not required for use.

In the accompanying drawings, Figure 1 is an elevation or face view of a drawing board embodying the invention, one of the holding clips being removed. Fig. 2 is a perspective view of such a clip, and Fig. 3 is a transverse section, corresponding to the line A B of Fig. 1, both Fig. 2 and Fig. 3 being drawn to a larger scale than said Fig. 1. Figs. 4: and 5 are similar views to Figs. 2 and 3 showing modifications.

, In the example shown in Figs. 1, 2 and 3, two pairs of studs (1 7) are used, the studs a, b of each pair being spaced a definite distance apart and secured to a small metal plate 0, fixed as by screws, in a recess in the The drawing board (is may advantagoon-sly.

be formed of a three ply panel, suitably framed, as such a board is less liable to warp and. become untrue than a drawing. boardjase ordinarily constructed.

6:" are perforated clips for. holding, the paper. onthe studs a, b and boardid each formed of. thin sheet metal. of" an elastic nature-andb'ent to a more or less 0' shape incross sectionas shown, so as to be capable of being easilyand quickly. fitted. in place; over. the top edge offthe board; d and removed as and when required, and" so as, to offer no obstruction, wheninposn tion,,to. the passage off'a square over thenn Thetop edge and'the back surface. of the. b oardis, or mayv advantageously. be, recessed'as at Zf," to receive the springiclips 6 so that'the latter. willnot project beyond theedge a-nclback surface ofj'the board and? form obstructions.

When. drawingboards and sheets of drawingpaper. of difi'erentsizes are provided for, use, it will. be advantageous to provide all: off the. former. With holding studs. and all of. the latter with perforationsv of! standard gage and size.

Holding; studs and clip, devices accord: ingto the-invention can: be variously, modifiedf without departing from. the essential. features of "the. invention. Thus, 7 the studs. a and: 6 instead .2 offb'eingmcarried by a. plate secured @in arecessin .the front ofthe board, may as shown in Fig.5, ,becarriedlb'ya. plateic. fixed. to; the1backof'the board, and. preferably, in. a.. recesstherein, as shown, the.v studs. extending, through the b'oard'and projecting.to a small extent from the. front; surface. thereof. Also, the. clip. devices instead iofbeing, formed with openings. ofv round .shape, .as shown. in. Figs; 1, 2 and 3 to fit the studs, may be formed with openings in..the. formof? open ended-slots as shown in Fig. 4 to embrace thepins sidewiseandbearuagainst the sheet of perforated paper engaged with the pins.

VVhatiI. claim is 1; ,A .drawing board having near thetop edgewthereofl studs arranged. at a distance. apart; and. extending, upward only; to a: smallheight abovethe front surface ofthe board to enter andffit=correspondingly arranged and shapedholes in a sheet of drawingmaterial 1 and clip devices each formed of thin sheet material of an elastic character bent to extend around the top edge of the board and embrace the back and front surfaces of the board, the thin front portions of the clip devices being formed with openings to receive the studs and arranged parallel to the. front surface of the board so that when holding a sheet of drawing material inposition on the board and over the studs, they will offer practically no obstruction. tor the passage of a T square over them. 7

2. A drawing board having near the top edge thereof and at adistanceapart, pairs of. studs. extending upwardto only a small height above the vfrontsurface.ofsthe board to: receiveand-firmly hold in position a sheet offdrawing. paper having, sets of perforations therein corresponding. in position and diameterto the sets of studs, and'clip-devices formed" of thin sheet material" of an elastic. nature bent to extend around the top. edges of 'the board and to embrace the bacli and'front surfaces of the hoard, the

front portions of the. clip device beingfiat.

and. parallel. to the front surface of' the board and adapted to engage. with the studsand when holding. a sheet of'drawing material in place on the board, being substantially flush with the freeends of the studsso that the fastening means will ofler practlcallyno obstruction to the passage of a. T square over them.

3. A drawing board having. at each of a number of" positions a. recess in the back and arecess in one edge, bodily removable,

clips each of thin sheet metal having a plane surface adapted" to lie fiat uponthe face of the drawing board and'also plane surfaces occupyingone such back and edge" recess and studs permanently attached to the-front of the b'oardinthe regions adapted to be covered by the front'piort-ions of the clips, said studs being. of alengthapproximately equalto the thickness of said front portions ofv the clips and the latter having. openings therein to receive the studs, the whole beingadapted to permit'a pierced sheet of drawing. material to be placed in position on the board, removed and re.- placed' again in exactly the same position and offering practically no obstruction to the manipulation of: a Tfsquare over the board.

4; A drawingboard having at each of a number of positions, a recess in the front, a recess in the back and a recess in the edge and'combined 'therewith means in the front recess-having projecting-parts adapted to. receive a perforated sheet of. paper, and

a spring clip adapted to be received by recesses in the back and edge of the. board and to engage the projecting parts ofthe means in the front recess.

5. A drawing board having at each of two Widely separated positions along one edge, a recess in the front, a recess in the back and a recess in the edge and combined 5 therewith, means in each front recess having a pair of projecting studs adapted to receive a correspondingly perforated sheet of paper, and spring clips each adapted to be received by a recess in the back and edge of the board and to engage the projecting studs.

Signed at Bembridge, Isle of Wight, England, this 3rd day of February, 1919. JOHN ISAAC THORNYCROFT.

copies of this patent my be obtained for five cents each, by addressing the commissioner of Eaten", walhington, D. 0." 

